A dedicated thread to discuss only the feedback on the completion kit and chassis has been set up:
https://www.diyaudio.com/forums/the...7-korg-b1-completion-kit-feedback-thread.html
Once the feedback loop is complete, that thread will be closed. Anything not specifically about the pioneer batch of completion kits posted in that thread will be moved back to this one.
https://www.diyaudio.com/forums/the...7-korg-b1-completion-kit-feedback-thread.html
Once the feedback loop is complete, that thread will be closed. Anything not specifically about the pioneer batch of completion kits posted in that thread will be moved back to this one.
Very nice build! I'm in the mood to mangle mine up a bit more so...
+1 on this question. And other than changing the caps indicated, were there other modifications?
What attenuator is that?
And, what are your impressions on the sound? I assume you never heard the difference between a "stock" build and yours, but I'm curious as to your satisfaction with the results.
+1 on this question. And other than changing the caps indicated, were there other modifications?
What attenuator is that?
And, what are your impressions on the sound? I assume you never heard the difference between a "stock" build and yours, but I'm curious as to your satisfaction with the results.
I posted build notes on the new Korg B1 thread... But I just set it up and have the following observations....See image. Hardly a reference system, but without any switching control I can't blow up the family with just having a single source and taking over our main system just yet. So I took my older speakers and attached them to my workstation Mac Pro as the input with a single ACA I made with my daughter. Listened to that for a while and it sounded great in a smallish office. Made the second ACA and now have more power—sounded even better—bridged-mono. Now I've added the B1 Korg. To test the inputs—saved by 6L6 last night—I connected the Mac Pro, and that older iPod in the picture. WTH? The old iPod sounds pretty incredible—a lot less volume required compared to the Mac Pro (better components as a stand-alone device???). I swear I'm hearing more detail and finesse as well. This is with a good cable to the Mac Pro and a not-good cable to the old iPod. I guess I should switch them at the B1 to rule out some wiring thing I might have done.
Then I switched the speaker wires... Uh. Yea—even more clarity to me, no question. This is the second harmonic stuff? Still reading through all of that. I think I have it right in my head according to Nelson's paper. It's kinda unreal. I didn't expect to hear a difference—but it's pretty serious. If I was to separate the speakers and get them off the floor a bit I'd probably pass out from the goodness.
FYI—the music I'm using for these listening tests I know well on vinyl and DAC in my main system. Room is different of course and amp is an NAD. Ahmad Jamal, Live at the Pershing and any Adele, since her vocals are ridiculous, and frequently Graceland (Paul Simon), Take Five—Brubeck is solid too. I think that stuff matters... but everyone has different tastes.
I did notice some "ringing" that some people have noted, audible from the B1 itself, not in the speakers. That was on power up with inputs connected but I can't hear it when there's any volume at all. I'm not going to worry about it at the moment...Sounds incredible to me.
I should also note—maybe someone can tell me why—I'm getting A LOT more range out of the volume with the B1 in the chain. I could run the Mac Pro and the old iPod flat out max directly connected to the ACAs and not have it be loud enough for me personally—not that one could have a conversation at the volume I'm referring to. With the B1 in the chain I can get this thing LOUD. I'm at about 2 o'clock on the dial. 88db speakers.
BUILD THIS! you CANNOT get this at Best Buy—OMG.
Then I switched the speaker wires... Uh. Yea—even more clarity to me, no question. This is the second harmonic stuff? Still reading through all of that. I think I have it right in my head according to Nelson's paper. It's kinda unreal. I didn't expect to hear a difference—but it's pretty serious. If I was to separate the speakers and get them off the floor a bit I'd probably pass out from the goodness.
FYI—the music I'm using for these listening tests I know well on vinyl and DAC in my main system. Room is different of course and amp is an NAD. Ahmad Jamal, Live at the Pershing and any Adele, since her vocals are ridiculous, and frequently Graceland (Paul Simon), Take Five—Brubeck is solid too. I think that stuff matters... but everyone has different tastes.
I did notice some "ringing" that some people have noted, audible from the B1 itself, not in the speakers. That was on power up with inputs connected but I can't hear it when there's any volume at all. I'm not going to worry about it at the moment...Sounds incredible to me.
I should also note—maybe someone can tell me why—I'm getting A LOT more range out of the volume with the B1 in the chain. I could run the Mac Pro and the old iPod flat out max directly connected to the ACAs and not have it be loud enough for me personally—not that one could have a conversation at the volume I'm referring to. With the B1 in the chain I can get this thing LOUD. I'm at about 2 o'clock on the dial. 88db speakers.
BUILD THIS! you CANNOT get this at Best Buy—OMG.
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The B1k has about 16dB of gain. The B1s are buffers but the Nutude has gain. That should be the reason for the changes in volume position if nothing else changed.
Still have issue with this common build off Korg Nutube and Aleph 1.7. Hum when something connected at the RCA inputs. Isolated from ground by input. Signal goes from input to Potentiometer and to Korg. From Korg to Aleph 1.7 and to output. Ground connection from both to the supply for Aleph 1.7. Should I drop that connection and connect ground at the RCA inputs at chassis near input with 10 ohm resistors? I have not worked with this for several months. The hum is only when I connect signal to the RCA.
The only chassis connection I have for the Korg are the "native" via the PCB mounting screws. Everything else are isolated. I use an external switcher and have some additional filtering in the chassis to remove as much switching noise as possible.
I have a small peak at about 280 Hz which is more than 100 dB and is not audible so I decided to let it be. It originates form the PSU. But no hum.
It is difficult to get an overview of your build but if hum is only there when you connect something to the input it seems to be a "ground loop"? ….if only one RCA input is connected is hum still there?
I have a small peak at about 280 Hz which is more than 100 dB and is not audible so I decided to let it be. It originates form the PSU. But no hum.
It is difficult to get an overview of your build but if hum is only there when you connect something to the input it seems to be a "ground loop"? ….if only one RCA input is connected is hum still there?
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I am impressed you made a filter, and one that might actually be decent. What value is the series R?
The series R after the common mode choke is a 1 ohm resistor. It was to fine tune the voltage on the Korg PCB as I use small ferrite chokes instead of 10 ohm resistors. The ferrite chokes are about 9 ohm only. I was able to hit the right voltage that way. But I think it would work fine also without the 1 ohm resistor. The voltage drop over it is quite small.
I used a FocusRite as external sound card and Arta software. FocusRite was set to full Monitor (turned all the way up) and input sensitivity was set just before clipping (so just before the led turns red). I can see from the attached picture that vol. setting is about 11-o'clock. Internal generator was used set to -6 dB (as far as I remember). So I don't have the exact output voltage of Korg for the measurement. Maybe it can be estimated from the mentioned observations.....
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Thanks. Just wondering how yours measured against the published figures in the distortion vs. output chart.
nash
50k or 100k will be fine.
Assuming these are genuine BB, then it is indeed an excellent potentiometer I use since decades. But nowadays I see mainly fakes and for my B1 Korg I used with great results the Tocos Cosmos I mentioned in my posts. Non expensive and very very good, so worth a try IMHO.
Have fun
Claude
Assuming these are genuine BB, then it is indeed an excellent potentiometer I use since decades. But nowadays I see mainly fakes and for my B1 Korg I used with great results the Tocos Cosmos I mentioned in my posts. Non expensive and very very good, so worth a try IMHO.
Have fun
Claude
I use a 10k blue ALPS Japan in my Korg. I hand selected one where channel match was "spot on".
The distortion figures I measured was on par with the official figures. The funny thing with this amp is that I liked it very much driving my MoFo's. Now MoFo in on "pension" while I use my M2X amps. In the moment I use Starving Student II to drive M2X but I will try Korg also. There are so many combinations also with M2X input boards.
The distortion figures I measured was on par with the official figures. The funny thing with this amp is that I liked it very much driving my MoFo's. Now MoFo in on "pension" while I use my M2X amps. In the moment I use Starving Student II to drive M2X but I will try Korg also. There are so many combinations also with M2X input boards.
Ah, the old chestnut - stuff from China bad, from everywhere else good.
Apologies for the diversion but 99% of the electronics stuff nowadays is made in China - your iPhone, your computer, your TV no matter what brand it is, your washing machine, your fridge, most of the parts for your car, etc., etc.
A little bit of perspective please.